Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[wrt350n-kernel.git] / fs / super.c
blob9227c74005cc068362af334fd29aad673bdbd473
1 /*
2 * linux/fs/super.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * super.c contains code to handle: - mount structures
7 * - super-block tables
8 * - filesystem drivers list
9 * - mount system call
10 * - umount system call
11 * - ustat system call
13 * GK 2/5/95 - Changed to support mounting the root fs via NFS
15 * Added kerneld support: Jacques Gelinas and Bjorn Ekwall
16 * Added change_root: Werner Almesberger & Hans Lermen, Feb '96
17 * Added options to /proc/mounts:
18 * Torbjörn Lindh (torbjorn.lindh@gopta.se), April 14, 1996.
19 * Added devfs support: Richard Gooch <rgooch@atnf.csiro.au>, 13-JAN-1998
20 * Heavily rewritten for 'one fs - one tree' dcache architecture. AV, Mar 2000
23 #include <linux/module.h>
24 #include <linux/slab.h>
25 #include <linux/init.h>
26 #include <linux/smp_lock.h>
27 #include <linux/acct.h>
28 #include <linux/blkdev.h>
29 #include <linux/quotaops.h>
30 #include <linux/namei.h>
31 #include <linux/buffer_head.h> /* for fsync_super() */
32 #include <linux/mount.h>
33 #include <linux/security.h>
34 #include <linux/syscalls.h>
35 #include <linux/vfs.h>
36 #include <linux/writeback.h> /* for the emergency remount stuff */
37 #include <linux/idr.h>
38 #include <linux/kobject.h>
39 #include <linux/mutex.h>
40 #include <asm/uaccess.h>
43 LIST_HEAD(super_blocks);
44 DEFINE_SPINLOCK(sb_lock);
46 /**
47 * alloc_super - create new superblock
48 * @type: filesystem type superblock should belong to
50 * Allocates and initializes a new &struct super_block. alloc_super()
51 * returns a pointer new superblock or %NULL if allocation had failed.
53 static struct super_block *alloc_super(struct file_system_type *type)
55 struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER);
56 static struct super_operations default_op;
58 if (s) {
59 if (security_sb_alloc(s)) {
60 kfree(s);
61 s = NULL;
62 goto out;
64 INIT_LIST_HEAD(&s->s_dirty);
65 INIT_LIST_HEAD(&s->s_io);
66 INIT_LIST_HEAD(&s->s_more_io);
67 INIT_LIST_HEAD(&s->s_files);
68 INIT_LIST_HEAD(&s->s_instances);
69 INIT_HLIST_HEAD(&s->s_anon);
70 INIT_LIST_HEAD(&s->s_inodes);
71 init_rwsem(&s->s_umount);
72 mutex_init(&s->s_lock);
73 lockdep_set_class(&s->s_umount, &type->s_umount_key);
75 * The locking rules for s_lock are up to the
76 * filesystem. For example ext3fs has different
77 * lock ordering than usbfs:
79 lockdep_set_class(&s->s_lock, &type->s_lock_key);
80 down_write(&s->s_umount);
81 s->s_count = S_BIAS;
82 atomic_set(&s->s_active, 1);
83 mutex_init(&s->s_vfs_rename_mutex);
84 mutex_init(&s->s_dquot.dqio_mutex);
85 mutex_init(&s->s_dquot.dqonoff_mutex);
86 init_rwsem(&s->s_dquot.dqptr_sem);
87 init_waitqueue_head(&s->s_wait_unfrozen);
88 s->s_maxbytes = MAX_NON_LFS;
89 s->dq_op = sb_dquot_ops;
90 s->s_qcop = sb_quotactl_ops;
91 s->s_op = &default_op;
92 s->s_time_gran = 1000000000;
94 out:
95 return s;
98 /**
99 * destroy_super - frees a superblock
100 * @s: superblock to free
102 * Frees a superblock.
104 static inline void destroy_super(struct super_block *s)
106 security_sb_free(s);
107 kfree(s->s_subtype);
108 kfree(s->s_options);
109 kfree(s);
112 /* Superblock refcounting */
115 * Drop a superblock's refcount. Returns non-zero if the superblock was
116 * destroyed. The caller must hold sb_lock.
118 int __put_super(struct super_block *sb)
120 int ret = 0;
122 if (!--sb->s_count) {
123 destroy_super(sb);
124 ret = 1;
126 return ret;
130 * Drop a superblock's refcount.
131 * Returns non-zero if the superblock is about to be destroyed and
132 * at least is already removed from super_blocks list, so if we are
133 * making a loop through super blocks then we need to restart.
134 * The caller must hold sb_lock.
136 int __put_super_and_need_restart(struct super_block *sb)
138 /* check for race with generic_shutdown_super() */
139 if (list_empty(&sb->s_list)) {
140 /* super block is removed, need to restart... */
141 __put_super(sb);
142 return 1;
144 /* can't be the last, since s_list is still in use */
145 sb->s_count--;
146 BUG_ON(sb->s_count == 0);
147 return 0;
151 * put_super - drop a temporary reference to superblock
152 * @sb: superblock in question
154 * Drops a temporary reference, frees superblock if there's no
155 * references left.
157 static void put_super(struct super_block *sb)
159 spin_lock(&sb_lock);
160 __put_super(sb);
161 spin_unlock(&sb_lock);
166 * deactivate_super - drop an active reference to superblock
167 * @s: superblock to deactivate
169 * Drops an active reference to superblock, acquiring a temprory one if
170 * there is no active references left. In that case we lock superblock,
171 * tell fs driver to shut it down and drop the temporary reference we
172 * had just acquired.
174 void deactivate_super(struct super_block *s)
176 struct file_system_type *fs = s->s_type;
177 if (atomic_dec_and_lock(&s->s_active, &sb_lock)) {
178 s->s_count -= S_BIAS-1;
179 spin_unlock(&sb_lock);
180 DQUOT_OFF(s);
181 down_write(&s->s_umount);
182 fs->kill_sb(s);
183 put_filesystem(fs);
184 put_super(s);
188 EXPORT_SYMBOL(deactivate_super);
191 * grab_super - acquire an active reference
192 * @s: reference we are trying to make active
194 * Tries to acquire an active reference. grab_super() is used when we
195 * had just found a superblock in super_blocks or fs_type->fs_supers
196 * and want to turn it into a full-blown active reference. grab_super()
197 * is called with sb_lock held and drops it. Returns 1 in case of
198 * success, 0 if we had failed (superblock contents was already dead or
199 * dying when grab_super() had been called).
201 static int grab_super(struct super_block *s) __releases(sb_lock)
203 s->s_count++;
204 spin_unlock(&sb_lock);
205 down_write(&s->s_umount);
206 if (s->s_root) {
207 spin_lock(&sb_lock);
208 if (s->s_count > S_BIAS) {
209 atomic_inc(&s->s_active);
210 s->s_count--;
211 spin_unlock(&sb_lock);
212 return 1;
214 spin_unlock(&sb_lock);
216 up_write(&s->s_umount);
217 put_super(s);
218 yield();
219 return 0;
223 * Superblock locking. We really ought to get rid of these two.
225 void lock_super(struct super_block * sb)
227 get_fs_excl();
228 mutex_lock(&sb->s_lock);
231 void unlock_super(struct super_block * sb)
233 put_fs_excl();
234 mutex_unlock(&sb->s_lock);
237 EXPORT_SYMBOL(lock_super);
238 EXPORT_SYMBOL(unlock_super);
241 * Write out and wait upon all dirty data associated with this
242 * superblock. Filesystem data as well as the underlying block
243 * device. Takes the superblock lock. Requires a second blkdev
244 * flush by the caller to complete the operation.
246 void __fsync_super(struct super_block *sb)
248 sync_inodes_sb(sb, 0);
249 DQUOT_SYNC(sb);
250 lock_super(sb);
251 if (sb->s_dirt && sb->s_op->write_super)
252 sb->s_op->write_super(sb);
253 unlock_super(sb);
254 if (sb->s_op->sync_fs)
255 sb->s_op->sync_fs(sb, 1);
256 sync_blockdev(sb->s_bdev);
257 sync_inodes_sb(sb, 1);
261 * Write out and wait upon all dirty data associated with this
262 * superblock. Filesystem data as well as the underlying block
263 * device. Takes the superblock lock.
265 int fsync_super(struct super_block *sb)
267 __fsync_super(sb);
268 return sync_blockdev(sb->s_bdev);
272 * generic_shutdown_super - common helper for ->kill_sb()
273 * @sb: superblock to kill
275 * generic_shutdown_super() does all fs-independent work on superblock
276 * shutdown. Typical ->kill_sb() should pick all fs-specific objects
277 * that need destruction out of superblock, call generic_shutdown_super()
278 * and release aforementioned objects. Note: dentries and inodes _are_
279 * taken care of and do not need specific handling.
281 * Upon calling this function, the filesystem may no longer alter or
282 * rearrange the set of dentries belonging to this super_block, nor may it
283 * change the attachments of dentries to inodes.
285 void generic_shutdown_super(struct super_block *sb)
287 const struct super_operations *sop = sb->s_op;
289 if (sb->s_root) {
290 shrink_dcache_for_umount(sb);
291 fsync_super(sb);
292 lock_super(sb);
293 sb->s_flags &= ~MS_ACTIVE;
294 /* bad name - it should be evict_inodes() */
295 invalidate_inodes(sb);
296 lock_kernel();
298 if (sop->write_super && sb->s_dirt)
299 sop->write_super(sb);
300 if (sop->put_super)
301 sop->put_super(sb);
303 /* Forget any remaining inodes */
304 if (invalidate_inodes(sb)) {
305 printk("VFS: Busy inodes after unmount of %s. "
306 "Self-destruct in 5 seconds. Have a nice day...\n",
307 sb->s_id);
310 unlock_kernel();
311 unlock_super(sb);
313 spin_lock(&sb_lock);
314 /* should be initialized for __put_super_and_need_restart() */
315 list_del_init(&sb->s_list);
316 list_del(&sb->s_instances);
317 spin_unlock(&sb_lock);
318 up_write(&sb->s_umount);
321 EXPORT_SYMBOL(generic_shutdown_super);
324 * sget - find or create a superblock
325 * @type: filesystem type superblock should belong to
326 * @test: comparison callback
327 * @set: setup callback
328 * @data: argument to each of them
330 struct super_block *sget(struct file_system_type *type,
331 int (*test)(struct super_block *,void *),
332 int (*set)(struct super_block *,void *),
333 void *data)
335 struct super_block *s = NULL;
336 struct super_block *old;
337 int err;
339 retry:
340 spin_lock(&sb_lock);
341 if (test) {
342 list_for_each_entry(old, &type->fs_supers, s_instances) {
343 if (!test(old, data))
344 continue;
345 if (!grab_super(old))
346 goto retry;
347 if (s)
348 destroy_super(s);
349 return old;
352 if (!s) {
353 spin_unlock(&sb_lock);
354 s = alloc_super(type);
355 if (!s)
356 return ERR_PTR(-ENOMEM);
357 goto retry;
360 err = set(s, data);
361 if (err) {
362 spin_unlock(&sb_lock);
363 destroy_super(s);
364 return ERR_PTR(err);
366 s->s_type = type;
367 strlcpy(s->s_id, type->name, sizeof(s->s_id));
368 list_add_tail(&s->s_list, &super_blocks);
369 list_add(&s->s_instances, &type->fs_supers);
370 spin_unlock(&sb_lock);
371 get_filesystem(type);
372 return s;
375 EXPORT_SYMBOL(sget);
377 void drop_super(struct super_block *sb)
379 up_read(&sb->s_umount);
380 put_super(sb);
383 EXPORT_SYMBOL(drop_super);
385 static inline void write_super(struct super_block *sb)
387 lock_super(sb);
388 if (sb->s_root && sb->s_dirt)
389 if (sb->s_op->write_super)
390 sb->s_op->write_super(sb);
391 unlock_super(sb);
395 * Note: check the dirty flag before waiting, so we don't
396 * hold up the sync while mounting a device. (The newly
397 * mounted device won't need syncing.)
399 void sync_supers(void)
401 struct super_block *sb;
403 spin_lock(&sb_lock);
404 restart:
405 list_for_each_entry(sb, &super_blocks, s_list) {
406 if (sb->s_dirt) {
407 sb->s_count++;
408 spin_unlock(&sb_lock);
409 down_read(&sb->s_umount);
410 write_super(sb);
411 up_read(&sb->s_umount);
412 spin_lock(&sb_lock);
413 if (__put_super_and_need_restart(sb))
414 goto restart;
417 spin_unlock(&sb_lock);
421 * Call the ->sync_fs super_op against all filesystems which are r/w and
422 * which implement it.
424 * This operation is careful to avoid the livelock which could easily happen
425 * if two or more filesystems are being continuously dirtied. s_need_sync_fs
426 * is used only here. We set it against all filesystems and then clear it as
427 * we sync them. So redirtied filesystems are skipped.
429 * But if process A is currently running sync_filesystems and then process B
430 * calls sync_filesystems as well, process B will set all the s_need_sync_fs
431 * flags again, which will cause process A to resync everything. Fix that with
432 * a local mutex.
434 * (Fabian) Avoid sync_fs with clean fs & wait mode 0
436 void sync_filesystems(int wait)
438 struct super_block *sb;
439 static DEFINE_MUTEX(mutex);
441 mutex_lock(&mutex); /* Could be down_interruptible */
442 spin_lock(&sb_lock);
443 list_for_each_entry(sb, &super_blocks, s_list) {
444 if (!sb->s_op->sync_fs)
445 continue;
446 if (sb->s_flags & MS_RDONLY)
447 continue;
448 sb->s_need_sync_fs = 1;
451 restart:
452 list_for_each_entry(sb, &super_blocks, s_list) {
453 if (!sb->s_need_sync_fs)
454 continue;
455 sb->s_need_sync_fs = 0;
456 if (sb->s_flags & MS_RDONLY)
457 continue; /* hm. Was remounted r/o meanwhile */
458 sb->s_count++;
459 spin_unlock(&sb_lock);
460 down_read(&sb->s_umount);
461 if (sb->s_root && (wait || sb->s_dirt))
462 sb->s_op->sync_fs(sb, wait);
463 up_read(&sb->s_umount);
464 /* restart only when sb is no longer on the list */
465 spin_lock(&sb_lock);
466 if (__put_super_and_need_restart(sb))
467 goto restart;
469 spin_unlock(&sb_lock);
470 mutex_unlock(&mutex);
474 * get_super - get the superblock of a device
475 * @bdev: device to get the superblock for
477 * Scans the superblock list and finds the superblock of the file system
478 * mounted on the device given. %NULL is returned if no match is found.
481 struct super_block * get_super(struct block_device *bdev)
483 struct super_block *sb;
485 if (!bdev)
486 return NULL;
488 spin_lock(&sb_lock);
489 rescan:
490 list_for_each_entry(sb, &super_blocks, s_list) {
491 if (sb->s_bdev == bdev) {
492 sb->s_count++;
493 spin_unlock(&sb_lock);
494 down_read(&sb->s_umount);
495 if (sb->s_root)
496 return sb;
497 up_read(&sb->s_umount);
498 /* restart only when sb is no longer on the list */
499 spin_lock(&sb_lock);
500 if (__put_super_and_need_restart(sb))
501 goto rescan;
504 spin_unlock(&sb_lock);
505 return NULL;
508 EXPORT_SYMBOL(get_super);
510 struct super_block * user_get_super(dev_t dev)
512 struct super_block *sb;
514 spin_lock(&sb_lock);
515 rescan:
516 list_for_each_entry(sb, &super_blocks, s_list) {
517 if (sb->s_dev == dev) {
518 sb->s_count++;
519 spin_unlock(&sb_lock);
520 down_read(&sb->s_umount);
521 if (sb->s_root)
522 return sb;
523 up_read(&sb->s_umount);
524 /* restart only when sb is no longer on the list */
525 spin_lock(&sb_lock);
526 if (__put_super_and_need_restart(sb))
527 goto rescan;
530 spin_unlock(&sb_lock);
531 return NULL;
534 asmlinkage long sys_ustat(unsigned dev, struct ustat __user * ubuf)
536 struct super_block *s;
537 struct ustat tmp;
538 struct kstatfs sbuf;
539 int err = -EINVAL;
541 s = user_get_super(new_decode_dev(dev));
542 if (s == NULL)
543 goto out;
544 err = vfs_statfs(s->s_root, &sbuf);
545 drop_super(s);
546 if (err)
547 goto out;
549 memset(&tmp,0,sizeof(struct ustat));
550 tmp.f_tfree = sbuf.f_bfree;
551 tmp.f_tinode = sbuf.f_ffree;
553 err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0;
554 out:
555 return err;
559 * mark_files_ro
560 * @sb: superblock in question
562 * All files are marked read/only. We don't care about pending
563 * delete files so this should be used in 'force' mode only
566 static void mark_files_ro(struct super_block *sb)
568 struct file *f;
570 file_list_lock();
571 list_for_each_entry(f, &sb->s_files, f_u.fu_list) {
572 if (S_ISREG(f->f_path.dentry->d_inode->i_mode) && file_count(f))
573 f->f_mode &= ~FMODE_WRITE;
575 file_list_unlock();
579 * do_remount_sb - asks filesystem to change mount options.
580 * @sb: superblock in question
581 * @flags: numeric part of options
582 * @data: the rest of options
583 * @force: whether or not to force the change
585 * Alters the mount options of a mounted file system.
587 int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
589 int retval;
591 #ifdef CONFIG_BLOCK
592 if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev))
593 return -EACCES;
594 #endif
595 if (flags & MS_RDONLY)
596 acct_auto_close(sb);
597 shrink_dcache_sb(sb);
598 fsync_super(sb);
600 /* If we are remounting RDONLY and current sb is read/write,
601 make sure there are no rw files opened */
602 if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) {
603 if (force)
604 mark_files_ro(sb);
605 else if (!fs_may_remount_ro(sb))
606 return -EBUSY;
607 DQUOT_OFF(sb);
610 if (sb->s_op->remount_fs) {
611 lock_super(sb);
612 retval = sb->s_op->remount_fs(sb, &flags, data);
613 unlock_super(sb);
614 if (retval)
615 return retval;
617 sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
618 return 0;
621 static void do_emergency_remount(unsigned long foo)
623 struct super_block *sb;
625 spin_lock(&sb_lock);
626 list_for_each_entry(sb, &super_blocks, s_list) {
627 sb->s_count++;
628 spin_unlock(&sb_lock);
629 down_read(&sb->s_umount);
630 if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) {
632 * ->remount_fs needs lock_kernel().
634 * What lock protects sb->s_flags??
636 lock_kernel();
637 do_remount_sb(sb, MS_RDONLY, NULL, 1);
638 unlock_kernel();
640 drop_super(sb);
641 spin_lock(&sb_lock);
643 spin_unlock(&sb_lock);
644 printk("Emergency Remount complete\n");
647 void emergency_remount(void)
649 pdflush_operation(do_emergency_remount, 0);
653 * Unnamed block devices are dummy devices used by virtual
654 * filesystems which don't use real block-devices. -- jrs
657 static struct idr unnamed_dev_idr;
658 static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */
660 int set_anon_super(struct super_block *s, void *data)
662 int dev;
663 int error;
665 retry:
666 if (idr_pre_get(&unnamed_dev_idr, GFP_ATOMIC) == 0)
667 return -ENOMEM;
668 spin_lock(&unnamed_dev_lock);
669 error = idr_get_new(&unnamed_dev_idr, NULL, &dev);
670 spin_unlock(&unnamed_dev_lock);
671 if (error == -EAGAIN)
672 /* We raced and lost with another CPU. */
673 goto retry;
674 else if (error)
675 return -EAGAIN;
677 if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) {
678 spin_lock(&unnamed_dev_lock);
679 idr_remove(&unnamed_dev_idr, dev);
680 spin_unlock(&unnamed_dev_lock);
681 return -EMFILE;
683 s->s_dev = MKDEV(0, dev & MINORMASK);
684 return 0;
687 EXPORT_SYMBOL(set_anon_super);
689 void kill_anon_super(struct super_block *sb)
691 int slot = MINOR(sb->s_dev);
693 generic_shutdown_super(sb);
694 spin_lock(&unnamed_dev_lock);
695 idr_remove(&unnamed_dev_idr, slot);
696 spin_unlock(&unnamed_dev_lock);
699 EXPORT_SYMBOL(kill_anon_super);
701 void __init unnamed_dev_init(void)
703 idr_init(&unnamed_dev_idr);
706 void kill_litter_super(struct super_block *sb)
708 if (sb->s_root)
709 d_genocide(sb->s_root);
710 kill_anon_super(sb);
713 EXPORT_SYMBOL(kill_litter_super);
715 #ifdef CONFIG_BLOCK
716 static int set_bdev_super(struct super_block *s, void *data)
718 s->s_bdev = data;
719 s->s_dev = s->s_bdev->bd_dev;
720 return 0;
723 static int test_bdev_super(struct super_block *s, void *data)
725 return (void *)s->s_bdev == data;
728 int get_sb_bdev(struct file_system_type *fs_type,
729 int flags, const char *dev_name, void *data,
730 int (*fill_super)(struct super_block *, void *, int),
731 struct vfsmount *mnt)
733 struct block_device *bdev;
734 struct super_block *s;
735 int error = 0;
737 bdev = open_bdev_excl(dev_name, flags, fs_type);
738 if (IS_ERR(bdev))
739 return PTR_ERR(bdev);
742 * once the super is inserted into the list by sget, s_umount
743 * will protect the lockfs code from trying to start a snapshot
744 * while we are mounting
746 down(&bdev->bd_mount_sem);
747 s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);
748 up(&bdev->bd_mount_sem);
749 if (IS_ERR(s))
750 goto error_s;
752 if (s->s_root) {
753 if ((flags ^ s->s_flags) & MS_RDONLY) {
754 up_write(&s->s_umount);
755 deactivate_super(s);
756 error = -EBUSY;
757 goto error_bdev;
760 close_bdev_excl(bdev);
761 } else {
762 char b[BDEVNAME_SIZE];
764 s->s_flags = flags;
765 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
766 sb_set_blocksize(s, block_size(bdev));
767 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
768 if (error) {
769 up_write(&s->s_umount);
770 deactivate_super(s);
771 goto error;
774 s->s_flags |= MS_ACTIVE;
777 return simple_set_mnt(mnt, s);
779 error_s:
780 error = PTR_ERR(s);
781 error_bdev:
782 close_bdev_excl(bdev);
783 error:
784 return error;
787 EXPORT_SYMBOL(get_sb_bdev);
789 void kill_block_super(struct super_block *sb)
791 struct block_device *bdev = sb->s_bdev;
793 generic_shutdown_super(sb);
794 sync_blockdev(bdev);
795 close_bdev_excl(bdev);
798 EXPORT_SYMBOL(kill_block_super);
799 #endif
801 int get_sb_nodev(struct file_system_type *fs_type,
802 int flags, void *data,
803 int (*fill_super)(struct super_block *, void *, int),
804 struct vfsmount *mnt)
806 int error;
807 struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
809 if (IS_ERR(s))
810 return PTR_ERR(s);
812 s->s_flags = flags;
814 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
815 if (error) {
816 up_write(&s->s_umount);
817 deactivate_super(s);
818 return error;
820 s->s_flags |= MS_ACTIVE;
821 return simple_set_mnt(mnt, s);
824 EXPORT_SYMBOL(get_sb_nodev);
826 static int compare_single(struct super_block *s, void *p)
828 return 1;
831 int get_sb_single(struct file_system_type *fs_type,
832 int flags, void *data,
833 int (*fill_super)(struct super_block *, void *, int),
834 struct vfsmount *mnt)
836 struct super_block *s;
837 int error;
839 s = sget(fs_type, compare_single, set_anon_super, NULL);
840 if (IS_ERR(s))
841 return PTR_ERR(s);
842 if (!s->s_root) {
843 s->s_flags = flags;
844 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
845 if (error) {
846 up_write(&s->s_umount);
847 deactivate_super(s);
848 return error;
850 s->s_flags |= MS_ACTIVE;
852 do_remount_sb(s, flags, data, 0);
853 return simple_set_mnt(mnt, s);
856 EXPORT_SYMBOL(get_sb_single);
858 struct vfsmount *
859 vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)
861 struct vfsmount *mnt;
862 char *secdata = NULL;
863 int error;
865 if (!type)
866 return ERR_PTR(-ENODEV);
868 error = -ENOMEM;
869 mnt = alloc_vfsmnt(name);
870 if (!mnt)
871 goto out;
873 <<<<<<< HEAD:fs/super.c
874 if (data) {
875 =======
876 if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
877 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:fs/super.c
878 secdata = alloc_secdata();
879 if (!secdata)
880 goto out_mnt;
882 <<<<<<< HEAD:fs/super.c
883 error = security_sb_copy_data(type, data, secdata);
884 =======
885 error = security_sb_copy_data(data, secdata);
886 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:fs/super.c
887 if (error)
888 goto out_free_secdata;
891 error = type->get_sb(type, flags, name, data, mnt);
892 if (error < 0)
893 goto out_free_secdata;
894 BUG_ON(!mnt->mnt_sb);
896 error = security_sb_kern_mount(mnt->mnt_sb, secdata);
897 if (error)
898 goto out_sb;
900 mnt->mnt_mountpoint = mnt->mnt_root;
901 mnt->mnt_parent = mnt;
902 up_write(&mnt->mnt_sb->s_umount);
903 free_secdata(secdata);
904 return mnt;
905 out_sb:
906 dput(mnt->mnt_root);
907 up_write(&mnt->mnt_sb->s_umount);
908 deactivate_super(mnt->mnt_sb);
909 out_free_secdata:
910 free_secdata(secdata);
911 out_mnt:
912 free_vfsmnt(mnt);
913 out:
914 return ERR_PTR(error);
917 EXPORT_SYMBOL_GPL(vfs_kern_mount);
919 static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)
921 int err;
922 const char *subtype = strchr(fstype, '.');
923 if (subtype) {
924 subtype++;
925 err = -EINVAL;
926 if (!subtype[0])
927 goto err;
928 } else
929 subtype = "";
931 mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL);
932 err = -ENOMEM;
933 if (!mnt->mnt_sb->s_subtype)
934 goto err;
935 return mnt;
937 err:
938 mntput(mnt);
939 return ERR_PTR(err);
942 struct vfsmount *
943 do_kern_mount(const char *fstype, int flags, const char *name, void *data)
945 struct file_system_type *type = get_fs_type(fstype);
946 struct vfsmount *mnt;
947 if (!type)
948 return ERR_PTR(-ENODEV);
949 mnt = vfs_kern_mount(type, flags, name, data);
950 if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
951 !mnt->mnt_sb->s_subtype)
952 mnt = fs_set_subtype(mnt, fstype);
953 put_filesystem(type);
954 return mnt;
957 struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)
959 return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data);
962 EXPORT_SYMBOL_GPL(kern_mount_data);